Dental flask



W. D. KIRBY DENTAL FLASK May 23, 1939.

' Filed Aug. 12, 1937 ATTORNEYS Patented May 23, 1939 UNITED STATESPATENT oFFICE 2 Claims.

I My invention relates to the manufacture of dentures and includes amongits objects and advantages the provision of an improved dental flaskparticularly adapted for duplication work.

In the accompanying drawing:

Fig. l is an elevational View of my flask;

Fig. 2 is a view along the line 2--2 of Fig. l with a portion brokenaway for the sake of clearness;

Fig. 3 is a fragmentary view taken from the position indicated by line3-3 of Fig. 2;

Fig. 4 is a sectional View along the line 4-4 of Fig. 1;

Fig. 5 is a fragmentary view taken from the position indicated by line5-5 of Fig. 2; and

Fig. 6 is a fragmentary view taken from the position indicated by line6-5 of Fig. 5.

In the embodiment selected to illustrate my invention, the flaskcomprises a bottom section In, a middle section I2, a top section I4,and a cover I5 provided with an opening I'I. Middle section I2 is madeup of two parts I6 and I8, with the part I8 provided with two spacedflanges 20 between which the lug 22 carried by the part I6 is looselypositioned. Parts 23 and 22 are provided with aligned openings for thereception of a pin 24 which hingedly connects the parts I6 and I8. Fig.2 illustrates the parts I6 and I8 in their latched relation.

Part I8 carries a finger 26 which lies between lugs 28 on the part I6and extends a short distance beyond the lugs, as illustrated in Figs. 2and 3. Finger 25 includes an inwardly extending lug 30 spaced a shortdistance from the lugs 28. Parts I6 and I8 may be firmly latched in theposition of Fig. 2 by driving a tapered pin 32 between the lugs 28 onthe part I6 and the lug 30 carried by the finger 26.

Section I0 carries two spaced lugs 34 on opposite sides to have guidingrelation with pins 36 formed integrally with the section I2. These pinsextend above and below the top and bottom edges, respectively, of thesection I2, and the upper ends of the pins have guiding relation withlugs 38 carried by the section I2 on opposite sides in alignment withthe lugs 34. The upper ends of the pins 36 include inwardly projectinglugs 40, which lugs are spaced short distances from the lugs 38. Topsection I4 may be clamped firmly to the middle section I2 by drivingtapered pins 42 between the lugs 40 on the pins 36 and the lugs 38 onthe top section I4. Pins 32 and 42 may be serrated along one edge, as at44, for holding purposes, but good results have been secured with smoothpins.

In Fig. 4, I illustrate the denture generally at 46 while lines 48 and50 indicate generally lines of separation of the plaster encasing thedenture. Means are provided for fracturing the plaster in the middlesection I2 on the median line of the denture 46, as indicated'by dottedlines 52 in Fig. 2. To this end the parts I6 and I8 are provided withinwardly extending ribs or wings 54 and 56, respectively. In operation,sections I0, I2 and I4 are easily separated while the parts I6 and I8 ofsection I2 may be separated about the axis of the pin 24. The denture islocated in the middle section and is completely surrounded by plasterwhen the three sections of the flask are assembled. However, when theupper and lower sections of the flask are removed, both faces of thedenture are laid bare. Thus the denture will be surrounded by a bandonly of plaster, which band lies between the denture and the wall of themiddle section. The separation of the plaster in the upper and lowersections from the band remaining in the middle section is predeterminedin the usual manner.

Because of the wings 54 and 58, the plaster in section I2 will bedivided on a median line with respect to the denture 46 While the wingsare of such construction as to eifectively hold the plaster within thetwo parts. With the parts It and I8 separated, the denture 46 is easilyremoved from the investment. In separating the parts I6 and I8 with theplaster therein, a pointed tool may be driven between the wings 54 and56 adjacent the finger 26 for fracturing the plaster. Tapered pins 32and 42 perform a good clamping function with respect to the middle andtop sections l2 and I4, and are easily placed in position and removed.

The keys 32 and 42 draw the contacting edges of the sections I2 and I4into such pressure relat ion as to establish a complete seal, thuspreventing the escape of excess rubber incident to heating and pressingin the press. In establishing an effective seal about the abutting edgesof the sections I2 and I4, I prevent a generally darker base rubber frompenetrating natural colored rubber employed on the labial part of thedenture.

Without further elaboration, the foregoing will so fully explain myinvention that other may, by applying current knowledge, readily adaptthe same for use under various conditions of service.

I claim:

1. A dental flask comprising three separable sections, means for holdingthe sections in assembled relation, one of said sections comprising twoparts hingedly connected together, each of said parts having inwardlyprojecting wings arranged in abutting relation with the wings on theother part in the closed position of the parts, said wings being of suchconstruction and arrangement as to rupture the plaster in. the said onesection when said parts are pivoted outwardly about their axis.

2. A dental flask comprising a top section, a

bottom section and a middle section between the top and bottom sections,said middle section comprising two parts hingedly connected together,

. the parts of said middle section being provided with plaster rupturingmeans for dividing the plaster between a denture located therein and themiddle section when said parts are separated about the axis of theirpivotal connection.

WILLIAM D. KIRBY.

